The present invention relates to a novel class of ketoheterocyclic urea grease thickening agents for high temperature applications and to the novel grease compositions gelled therewith.
Grease compositions capable of providing effective lubrication at high temperature e.g., temperature of 300.degree. F to 400.degree. F, and above, have become increasingly important and numerous thickening agents have been proposed for use in such greases, e.g., soap base thickeners, inorganic clay thickeners and organic thickeners. Examples of the organic thickening agents include various polyureas, ureido compounds, amido compounds and the like. Such organic thickening agents are typically prepared by reacting one or more mono-, di- or polyamides with one or more mono-, di-, or polyisocyanates. The thickeners of this type generally produce greases having desirably high dropping points; however, they have frequently been found to have less than desirable properties in other important aspects, e.g., thermal and mechanical stability, high temperature bearing performance, oxidation and corrosion resistance, etc. The present invention provides a novel class of ketoheterocycle thickening agents which produce greases not only having desirable high dropping points but also excellent overall balance of properties.